1. Field of the Invention
The invention relates to a method for operating an open end power wrench. More particularly, the invention relates a method for controlling a drive socket on an open end power wrench by measuring parameters thereof.
2. Description of the Related Art
Open end power wrenches are used in the manufacturing of products. One type of an open end power wrench is a tube nut wrench. The tube nut wrench is designed to allow the operator thereof to tighten fasteners designed to secure hydraulic and/or pneumatic lines sharing a common centerline with the fastener. The tube nut wrench also facilitates the operator""s ability to maximize torque on a fastener or part when the location of the fastener or part does not allow the operator to have a mechanical advantage over the fastener or part being worked.
U.S. Pat. No. 5,363,698, issued to Estep et al. on Jun. 10, 1997, discloses a tube nut wrench. This tube nut wrench extends from a tube nut head to a handle. A power cable or air line extends out from a distal end of the handle. The power source provides power to the tube nut wrench.
In addition, the tube nut wrench disclosed in this reference does not have any means for regulating the speed or torque output of the drive socket as the drive socket rotates through its initial open-to-close rotation. More specifically, neither this reference nor any other tube nut wrench known includes a feature designed to vary or control the speed or torque of the drive socket as the drive socket moves from its starting position through its initial closed position. Such a feature is desirable because so often the drive socket is inadvertently placed on items that are not the item to be rotated. Another situation that occurs is when a fastener is not properly aligned. In this instance, full torque on the fastener may damage the fastener or part assembly.
The invention is a method for controlling a tube nut wrench. The tube nut wrench includes a tool engaging end, a motor, a switch electrically connected to the motor for selectively operating the motor, a transmission operatively connected to the motor, a housing defining a clearance opening, and a drive socket. The drive socket is connected to the transmission and rotatable with respect to the housing. The drive socket defines a socket opening equal to the clearance opening. The method includes the steps of operating the motor to generate an output torque. The method then measures an angle of rotation through which the drive socket rotates. The angle of rotation is then compared with an angle defined by the clearance opening. The output torque is limited to a minimal torque level when the angle of rotation of the drive socket is less than the angle defined by the clearance opening. The method then increases the output torque to an operating torque level when the angle of rotation of the drive socket exceeds the angle defined by the clearance opening.